Jessica Mauboy has admitted to feeling like a newcomer as she prepares for her big Eurovision moment in Copenhagen on Friday morning (Australian time).

Mauboy will perform what she calls a "goosebumps"-inducing song titled Sea Of Flags when she takes the stage at the Eurovision Song Contest just after 6.15am. She will perform in front of an estimated 20 million-plus viewers, arguably the biggest television audience any Australian has tackled since the Sydney Olympics.

"I'm still learning as I go – I don't know everything. It is pretty scary, you know, coming from Darwin, taking to stages around Australia and now getting this opportunity to go so much further, which is pretty much any artist's dream come true."

But Mauboy feels ready, especially after winning the prestigious ARIA Award for best female artist last November: "That felt bloody amazing ... It made me realise I'm on the right path, just being me, doing what I love and being a role model, and now I'm being recognised for that."

Eurovison Song Contest 2014

Mauboy says the Eurovision experience feels like a repeat of the earliest days of her career, when she was on Australian Idol in 2006. "Yes, it does feel like that. It feels like going through that cycle again and having to start again and introduce myself and my music again."

She added that the performance was not about taking risks. "This is me being the Jess who loves to perform and belting out big songs and celebrating through music."

Details of what the Australian star will perform have been kept tightly under wraps, but video from the semi-final dress rehearsal posted on the official Eurovision website does give viewers a sneak peek. The snippet shows Mauboy in a metallic dress singing Sea of Flags, an uptempo original song recorded especially for the performance.

'Dream come true': Jessica Mauboy. Photo: Getty Images

SBS has revealed the Australian and Aboriginal flags will be projected behind the singer as she performs. One photo from the rehearsal showed Mauboy beside an astronaut waving an Aboriginal flag.

Denmark's Hobart-born Crown Princess Mary was rumoured to be attending Mauboy's second dress rehearsal on Thursday morning (local time) and it is also thought the royal couple will attend the second semi-final when Mauboy performs.

Mauboy, who has only hinted at the subject matter of the song before, opened up on her official website.

"The song speaks of ancient dreaming but I also wanted to convey a message that whatever country you represent, you have to bring that culture to the next generation," she says.

"Every time I listen to it I get another layer of goosebumps, so introducing it to the world is going to be so powerful."

Mauboy wrote the song with Ilan Kidron, lead singer of dance music group The Potbelleez.

In the rehearsal clip, Mauboy's voice can be heard soaring in what sounds like a modern ballad pop star Rihanna might sing while the title Sea Of Flags appears on screen.

The singer is shown on stage at the B&W Hallerne in Copenhagen, wearing a gold peplum dress with a mullet skirt that billows dramatically behind her.

In Sydney, 300 people were expected to attend a live screening of the performance, above the Museum of Contemporary Art. The lights of the Sydney Harbour Bridge and Sydney Opera House.

SBS One will screen delayed coverage of the second semi-final from 7.30am on Friday. The channel's full Eurovision Song Contest coverage, featuring Julia Zemiro and Sam Pang and Mauboy's performance, screens Friday, Saturday and Sunday evening on SBS One.